An ultrasonic imaging apparatus that transmits pulsating ultrasonic waves to the inside of a living body and visualizing internal information on the living body using a receiving signal has the features of a compact apparatus and real-time image display, and is one of imaging apparatuses used versatilely in the field of medicine along with X ray and MRI.
Vascular contrast enhancement is generally known as a technique of obtaining an image in which a vascular network including microscopic structures is highlighted at a higher contrast than peripheral tissues are, and versatilely utilized in each imaging apparatus in clinical practice.
Used as an ultrasonic contrast medium are microscopic bubbles (micro-bubbles) of several micrometers in diameter. A reason why the microscopic bubbles are used lies in that the bubbles resonate with ultrasonic waves of several megahertz employed in a medical field, and bring about scattering waves in a frequency band equivalent to that of a transmitting/receiving pulsating signal. Contrast enhancement based on ultrasonic waves has such features that a contrast medium itself lacks both toxicity and critical invasiveness such as exposure, and that permits real-time observation of a contract-enhanced vessel, though, compared with other imaging apparatuses, a viewing field and a region capable of being imaged are limited.